In heating plants and in connection with heat storage units, it is a common practice to provide a three-way valve which can switch over flow from a source to either of two outlet paths. For that purpose, the valve may comprise a valve housing having a single inlet and two outlets, and a double valve assembly within the valve housing for alternatively connecting each of the two outlets with the inlet. The two valve bodies of this assembly can be held together by a common valve spindle which can be axially displaced by a control element.
In earlier three-way valve systems of this type, the inlet is rigidly fixed on the housing, a first outlet is disposed coaxial thereto and is usually also rigidly fixed with respect to the housing, while a second outlet is oriented at a right angle to the coaxial inlet and outlet. The flowing medium is thus deflected through a right angle upon switchover from the one outlet to the other outlet.
The controlled element may be an electric thermal valve actuator operating, for example, in response to a two-point controller.
The straight path through the valve housing can be blocked when the right angle path is fully opened and vice versa. Continuously operating controllers for actuating the valve spindle can also be used. In general, such continuous controllers can be proportional controllers operating without auxiliary energy forces and permitting intermediate positions of the valve to be obtained. With increasing temperature at a sensor, the straight passage is progressively closed and the angled passage progressively opened.
It has been found to be a disadvantage of these earlier valves that the orientation of the outlets does not always allow an installer to conveniently install the valve. The valve frequently must be installed with inconvenient piping runs to accommodate the piping system to the valve structure.
Alternatively, the installation must have available a stock of valves with outlets at different orientations. Both of these situations are inconvenient and costly.